What I don't understand is the example - 回复：想利用cruise给持B-1/2签证的父

What I don't understand is the example. It states "For instance, if you come to the U.S. on July 10, 2008 on a B2 Visitor Visa, you may go to Canada and/or Mexico on or after November 10, and reenter the U.S. any time up until January 10" which contradicts "you may visit Canada, Mexico, or the Caribbean islands (not Cuba)for up to 30 days".

Maybe CBP incurs problem in calculating days between Nov 10 and Jan 10, or it may be a simple typo ("November 10" should be "December 10" actually).

DOS links, for reference.